Material removal device having improved material capture efficiency and methods of use

ABSTRACT

The present invention provides an improved atherectomy catheter having means for directing particles generated by a cutting element into a collection chamber. Methods of directing the cut material from a blood vessel lumen into a collection chamber are also provided.

This application is a continuation of U.S. patent application Ser. No.12/964,544, filed Dec. 9, 2010, which claims the benefit of U.S.Provisional Patent Application No. 61/285,768, filed Dec. 11, 2009,entitled “Material Removal Device Having Improved Material CaptureEfficiency and Methods of Use”, the contents of each of which are herebyincorporated by reference herein.

FIELD OF THE INVENTION

The present invention relates to catheters used to remove material froma site in a body lumen. More particularly, this invention pertains tocatheters capable of capturing the material removed from the site.

BACKGROUND OF THE INVENTION

Atherosclerosis is a progressive disease of the vascular system wherebyatheroma is deposited on the inner walls of blood vessels. Over timeatheromatous deposits can become large enough to reduce or occlude bloodflow through the vessels, leading to symptoms of low blood flow such aspain in the legs (on walking or at rest), skin ulcer, angina (at rest orexertional), and other symptoms. To treat this disease and improve orresolve these symptoms it is desirable to restore or improve blood flowthrough the vessel.

Various means are used to restore or improve blood flow throughatheromatous vessels. The atheroma deposits can be displaced bydiametrically expanding the vessel by inflating balloons, expandingstents, and other methods, however these methods undesirably tear andstretch the vessel, causing scar formation in a high percentage ofpatients. Such scar tissue (restenotic material), once formed, blocksflow in the vessel and often needs to be removed. The deposits can bepulverized using lasers and other methods however pulverization alone ofatheromatous material allows microemboli to flow downstream and lodge indistal vascular beds, further compromising blood flow to the tissueaffected by the disease. Atherectomy catheters can be used to removeatheromatous deposits from the blood vessel and can present an idealsolution when the atheromatous debris removed from the vessel iscaptured and removed from the body.

One problem that occurs when removing material from a blood vessel isthat material fragments may be created by the removal means, in somecases by a cutter, and such fragments may be left in the body where theycan embolize and cause problems. It is desirable to remove from the bodyall material fragments created at the time of material removal from avessel wall. Some catheters are designed to remove material from thebody by directing material particles into a collection chamber howeverthese collection efforts are not always 100% effective. Improvedparticle collection means are needed.

SUMMARY OF THE INVENTION

The invention provides an atherectomy catheter, comprising: a bodyhaving an opening; a rotatable shaft coupled to the body; a tissuecollection chamber coupled to the body and positioned distal to thecutting element; a cutting element coupled to the rotatable shaft, thecutting element having a cutting edge; and a lumen configured to directfluid into the tissue collection chamber.

The invention provides an atherectomy catheter, comprising: a bodyhaving an opening; a rotatable shaft coupled to the body; a tissuecollection chamber coupled to the body and positioned distal to thecutting element; a cutting element coupled to the rotatable shaft, thecutting element having a cutting edge; and a part for propelling fluiddistally in the tissue collection chamber, the part being selected fromthe group consisting of: (i) a drive shaft having a proximal end and adistal portion, the proximal end being attached to the cutting elementand a propeller being attached to the distal portion; and (ii) a paddleattached to the cutting element.

The invention provides a method of recirculating fluid in an atherectomycatheter comprising: providing an atherectomy catheter, the atherectomycatheter comprising: a body having an opening; a rotatable shaft coupledto the body; a tissue collection chamber coupled to the body andpositioned distal to the cutting element, the tissue collection chamberhaving vent holes; a cutting element coupled to the rotatable shaft, thecutting element having a cutting edge; and moving fluid out of thetissue collection chamber through the vent holes such that a negativepressure is created inside the tissue collection chamber and thisnegative pressure causing fluid to enter the tissue collection chamberthrough the opening of the body of the catheter.

The invention provides a method of removing material from a body lumen,the method comprising: providing an atherectomy catheter, theatherectomy catheter comprising: a body having an opening; a rotatableshaft coupled to the body; a tissue collection chamber coupled to thebody and positioned distal to the cutting element; a cutting elementcoupled to the rotatable shaft, the cutting element having a cuttingedge; and a lumen configured to direct fluid into the tissue collectionchamber; placing the catheter in the body lumen; and moving the catheterin the body lumen to contact the cutting element with the material inthe body lumen.

The invention provides a method of removing material from a body lumen,the method comprising: providing an atherectomy catheter, theatherectomy catheter comprising: a body having an opening; a rotatableshaft coupled to the body; a tissue collection chamber coupled to thebody and positioned distal to the cutting element; a cutting elementcoupled to the rotatable shaft, the cutting element having a cuttingedge; and a part for propelling fluid distally in the tissue collectionchamber, the part being selected from the group consisting of: (i) adrive shaft having a proximal end and a distal portion, the proximal endbeing attached to the cutting element and a propeller being attached tothe distal portion; and (ii) a paddle attached to the cutting element;placing the catheter in the body lumen; and moving the catheter in thebody lumen to contact the cutting element with the material in the bodylumen.

These and other aspects of the invention will become apparent from thefollowing description of the preferred embodiments, drawings and claims.The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the invention will be apparent from thedescription and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a partial isometric view of an atherectomy catheter.

FIG. 2 illustrates an isometric cross-sectional view of a portion of theatherectomy catheter illustrated in FIG. 1 with a cutting element in astored position.

FIG. 3 illustrates an isometric cross-sectional view of a portion of theatherectomy catheter illustrated in FIG. 1 with a cutting element in aworking position.

FIG. 4 illustrates an isometric view of an embodiment of a cuttingelement.

FIGS. 5, 6 and 7 illustrate partial cross-sectional views of distalportions of embodiments of a catheter having improved materialcollection.

FIG. 7A illustrates a partial cross-sectional side view of a portion ofthe catheter illustrated in FIG. 7.

FIG. 8 illustrates an isometric view of another embodiment of a cuttingelement.

FIG. 8A illustrates a cross sectional view of the cutting elementillustrated in FIG. 8.

FIG. 9 illustrates a partial cross-sectional view of a distal portion ofan embodiment of a catheter having improved material collection.

FIGS. 9A, 9B and 9C illustrate partial cross-sectional side views ofalternative components for the catheter illustrated in FIG. 9.

FIGS. 10A and 10B illustrate the catheter illustrated in FIG. 9 in usein a vessel.

DETAILED DESCRIPTION

The invention provides an atherectomy catheter, comprising: a bodyhaving an opening; a rotatable shaft coupled to the body; a tissuecollection chamber coupled to the body and positioned distal to thecutting element; a cutting element coupled to the rotatable shaft, thecutting element having a cutting edge; and a lumen configured to directfluid into the tissue collection chamber. In one embodiment, the lumendirects fluid in a distal direction into the tissue collection chamber.In one embodiment, the cutting element has a cup-shaped surface, thecup-shaped surface being configured to re-direct tissue cut by thecutting edge in a distal direction when the cup-shaped surface moves inthe distal direction. In one embodiment, the lumen has a distal openingon the cup-shaped surface of the cutting element. In an embodiment, thelumen comprises a first lumen portion in the cutting element and asecond lumen portion in the rotatable shaft. In one embodiment, thedistal opening is positioned at a longitudinal axis of the cuttingelement. In an embodiment, the lumen has a distal opening and the distalopening is not positioned on the cup-shaped surface of the cuttingelement. In one embodiment, the distal opening is positioned adjacent tothe cup-shaped surface of the cutting element.

In an embodiment, a fluid source that supplies fluid to the lumen isattached to a proximal portion of the catheter. In one embodiment, thefluid supplied by the fluid source is a saline solution. In oneembodiment, the fluid supplied by the fluid source comprises aradiopaque substance.

In an embodiment, a proximal opening of the lumen is positioned at adistal portion of the catheter but proximal of the cup-shaped surface ofthe cutting element. In one embodiment, the proximal opening ispositioned on the rotatable shaft. In one embodiment, the rotatableshaft comprises two or more proximal openings of the lumen. In anembodiment, the rotatable shaft comprises an impeller proximal of theproximal opening, the impeller forcing fluid into the proximal openingwhen the rotatable shaft is rotated. In one embodiment, the impeller has1 to 10 turns. In one embodiment, the lumen has a distal opening on thecup-shaped surface of the cutting element. In an embodiment, the distalopening is positioned at a longitudinal axis of the cutting element.

In one embodiment, a proximal opening of the lumen is positioned on thecutting element. In an embodiment, the proximal opening is positioned atan outer edge of the cutting element. In one embodiment, the cuttingelement has a cup-shaped surface, the cup-shaped surface beingconfigured to re-direct tissue cut by the cutting edge in a distaldirection when the cup-shaped surface moves in the distal direction, andthe lumen has a distal opening on the cup-shaped surface of the cuttingelement. In an embodiment, the distal opening is positioned at alongitudinal axis of the cutting element.

In an embodiment, the tissue collection chamber comprises vent holes. Inone embodiment, the tissue collection chamber comprises 10 to 200 ventholes. In an embodiment, the vent holes have a diameter of from 25 to200 microns. In an embodiment, the cutting element is movable between astored position and a cutting position relative to the opening.

The invention provides an atherectomy catheter, comprising: a bodyhaving an opening; a rotatable shaft coupled to the body; a tissuecollection chamber coupled to the body and positioned distal to thecutting element; a cutting element coupled to the rotatable shaft, thecutting element having a cutting edge; and a part for propelling fluiddistally in the tissue collection chamber, the part being selected fromthe group consisting of: (i) a drive shaft having a proximal end and adistal portion, the proximal end being attached to the cutting elementand a propeller being attached to the distal portion; and (ii) a paddleattached to the cutting element. In one embodiment, the cutting elementhas a cup-shaped surface, the cup-shaped surface being configured tore-direct tissue cut by the cutting edge in a distal direction when thecup-shaped surface moves in the distal direction. In an embodiment, thepart for propelling fluid distally in the tissue collection chamber isselected from the group consisting of: (i) a drive shaft having aproximal end and a distal portion, the proximal end being attached tothe cup-shaped surface of the cutting element and a propeller beingattached to the distal portion; and (ii) a paddle attached to thecup-shaped surface of the cutting element.

In an embodiment, the part for propelling fluid distally in the tissuecollection chamber is a drive shaft having a proximal end and a distalportion, the proximal end being attached to the cutting element and apropeller being attached to the distal portion. In one embodiment, thepropeller is located distally of the opening and proximally of thedistal end of the collection chamber. In an embodiment, the propeller islocated immediately distally of the opening. In an embodiment, thepropeller is located in the distal half of the collection chamber. Inone embodiment, the proximal end of the drive shaft is attached to acup-shaped surface of the cutting element, the cup-shaped surface beingconfigured to re-direct tissue cut by the cutting edge in a distaldirection when the cup-shaped surface moves in the distal direction.

In an embodiment, the part for propelling fluid distally in the tissuecollection chamber is a paddle attached to the cutting element. In anembodiment, the paddle is a wire that is twisted in a helicalconfiguration. In an embodiment, the wire has a rectangular crosssection. In an embodiment, the wire has a thickness from 0.002 to 0.020inch (0.0051 to 0.051 cm). In one embodiment, wire width is from 0.010to 0.075 inch (0.025 to 0.19 cm). In an embodiment, the paddle has awire width that is from 20 to 95 percent of an inside diameter of thecollection chamber. In an embodiment, the paddle has a longitudinallength that is at least 50 percent of the longitudinal length of thecollection chamber. In an embodiment, the paddle has a longitudinallength that is at least 70 percent of the longitudinal length of thecollection chamber. In an embodiment, the tissue collection chambercomprises vent holes. In one embodiment, the tissue collection chambercomprises 10 to 200 vent holes. In an embodiment, the vent holes have adiameter of from 25 to 200 microns. In an embodiment, the paddle isattached to a cup-shaped surface of the cutting element, the cup-shapedsurface being configured to re-direct tissue cut by the cutting edge ina distal direction when the cup-shaped surface moves in the distaldirection.

In one embodiment, the collection chamber comprises a portion at adistal end that can be opened to remove cut material and particles. Inan embodiment, the cutting element is movable between a stored positionand a cutting position relative to the opening.

The invention provides a method of recirculating fluid in an atherectomycatheter comprising: providing an atherectomy catheter, the atherectomycatheter comprising: a body having an opening; a rotatable shaft coupledto the body; a tissue collection chamber coupled to the body andpositioned distal to the cutting element, the tissue collection chamberhaving vent holes; a cutting element coupled to the rotatable shaft, thecutting element having a cutting edge; and moving fluid out of thetissue collection chamber through the vent holes such that a negativepressure is created inside the tissue collection chamber and thisnegative pressure causing fluid to enter the tissue collection chamberthrough the opening of the body of the catheter. In one embodiment, thecatheter comprises a lumen configured to direct fluid into the tissuecollection chamber. In an embodiment, the catheter comprises a part forpropelling fluid distally in the tissue collection chamber, the partbeing selected from the group consisting of: (i) a drive shaft having aproximal end and a distal portion, the proximal end being attached tothe cutting element and a propeller being attached to the distalportion; and (ii) a paddle attached to the cutting element.

The invention provides a method of removing material from a body lumen,the method comprising: providing an atherectomy catheter, theatherectomy catheter comprising: a body having an opening; a rotatableshaft coupled to the body; a tissue collection chamber coupled to thebody and positioned distal to the cutting element; a cutting elementcoupled to the rotatable shaft, the cutting element having a cuttingedge; and a lumen configured to direct fluid into the tissue collectionchamber; placing the catheter in the body lumen; and moving the catheterin the body lumen to contact the cutting element with the material inthe body lumen. In one embodiment, the catheter is moved in a distaldirection to contact the cutting edge with the material in the bodylumen. In one embodiment, the catheter is placed in the body lumen withthe cutting element in the stored position and the catheter is moved tocontact the material with the cutting element in a cutting position. Inone embodiment, the body lumen is a blood vessel.

The invention provides a method of removing material from a body lumen,the method comprising: providing an atherectomy catheter, theatherectomy catheter comprising: a body having an opening; a rotatableshaft coupled to the body; a tissue collection chamber coupled to thebody and positioned distal to the cutting element; a cutting elementcoupled to the rotatable shaft, the cutting element having a cuttingedge; and a part for propelling fluid distally in the tissue collectionchamber, the part being selected from the group consisting of: (i) adrive shaft having a proximal end and a distal portion, the proximal endbeing attached to the cutting element and a propeller being attached tothe distal portion; and (ii) a paddle attached to the cutting element;placing the catheter in the body lumen; and moving the catheter in thebody lumen to contact the cutting element with the material in the bodylumen. In one embodiment, the catheter is moved in a distal direction tocontact the cutting edge with the material in the body lumen. In oneembodiment, the catheter is placed in the body lumen with the cuttingelement in the stored position and the catheter is moved to contact thematerial with the cutting element in a cutting position. In oneembodiment, the body lumen is a blood vessel.

The present invention provides an improved atherectomy catheter havingfeatures for directing particles generated by a cutting element into acollection chamber. Methods of directing the cut material from a bloodvessel lumen into a collection chamber are also provided. The cuttingelement has a sharp cutting edge that surrounds a cup-shaped surface.Cut material is directed into the collection chamber by the cup-shapedsurface and by fluid flow.

Referring to FIGS. 1 to 4, an atherectomy catheter 2 is shown which hasa cutting element 4, which is used to cut material from a blood flowlumen such as a blood vessel. The cutting element 4 is movable between astored position (FIG. 2) and a cutting position (FIG. 3) relative to anopening 6 in a body 8 of the catheter 2. The cutting element 4 movesoutwardly relative to the opening 6 so that a portion of the element 4extends outwardly from the body 8 through the opening 6. In oneembodiment the cutting element 4 may be positioned relative to the body8 and opening 6 so that less than 90 degrees of the cutting element 4 isexposed to cut tissue. In other embodiments more of the cutting element4 may be exposed without departing from numerous aspects of theinvention.

Distal end of catheter 2 is positioned near a treatment site of a vesselwith cutting element 4 in the stored position. Then catheter 2 is moveddistally through the vessel with the cutting element 4 in the working orcutting position as described in further detail below. As the catheter 2moves through the blood vessel with the cutting element 4 in the workingor cutting position the tissue material is cut by the cutting element 4and is directed into a tissue chamber 12 positioned distal to thecutting element 4. The tissue chamber 12 may be somewhat elongated toaccommodate the tissue which has been cut.

To expose cutting element 4 through opening 6, cutting element 4 ismoved proximally from the stored position so that a cam surface 14 onthe cutting element 4 engages a ramp 16 on the body 8 of the catheter 2.The interaction between the cam surface 14 and the ramp 16 causes thecutting element 4 to move to the cutting position and also causes a tip18 to deflect which tends to move the cutting element 4 toward thetissue to be cut.

The cutting element 4 has a cup-shaped surface 24, which directs thetissue cut by the cutting edge 22 into the tissue chamber 12. Cuttingedge 22 may be at a radially outer edge 23 of the cutting element 4. Insome embodiments the cup-shaped surface 24 may be a smooth andcontinuous surface free of through holes, teeth, fins or other features,which disrupt the smooth nature of the surface 24 for at least half thedistance from the longitudinal axis LA to the outer radius at thecutting edge 22. In some embodiments the cup-shaped surface 24 may alsobe free of any such features throughout an area of at least 300 degreesrelative to the longitudinal axis LA. In other embodiments thecup-shaped surface may have a limited amount of through holes, teeth,fins or other features as described in further detail below. One or moreraised elements 26 may extend outwardly from the cup-shaped surface 24with FIG. 4 showing two raised elements 26. The raised element 26 is asmall wedge of material that rises relatively abruptly from thecup-shaped surface 24. The raised element 26 helps to break up hardtissue and plaque by applying a relatively blunt striking force to thehard tissue or plaque since cutting such tissue with the cutting edge 22may not be effective, and strips of such hard tissue may not be flexibleenough to be redirected by cup-shaped surface 24 into collection chamber12. The raised elements 26 altogether occupy a relative small part ofthe cup-shaped surface 24. By sizing and positioning the raised elements26 in this manner, the raised elements 26 do not interfere with theability of the cutting element 4 cup-shaped surface 24 to cut andre-direct large strips of tissue into the tissue chamber while stillproviding the ability to break up hard tissue and plaque with raisedelement 26.

The cutting element 4 is coupled to a shaft 20 that extends through alumen 21 in the catheter 2. Catheter 2 is coupled to exemplary cutterdriver 5. Cutter driver 5 is comprised of motor 11, power source 15 (forexample one or more batteries), microswitch (not shown), housing 17(upper half of housing is removed as shown), lever 13 and connectionassembly (not shown) for connecting shaft 20 to driver motor 11. Cutterdriver 5 can act as a handle for the user to manipulate catheter 2.Lever 13, when actuated to close the microswitch, electrically connectspower source 15 to motor 11 thereby causing rotation of cutting element4. The cutting element 4 is rotated about a longitudinal axis LA whenthe shaft 20 rotates. The cutting element 4 is rotated at about 1 to160,000 rpm but may be rotated at any other suitable speed dependingupon the particular application. Further description of catheterssimilar to catheter 2 is found in U.S. Patent Application PublicationNo. US 2002/0077642 A1 to Patel et. al., entitled “Debulking Catheter”,the contents of which are hereby incorporated by reference herein.

In use, catheter 2 cuts softer atheroma from a vessel wall in relativelylarge strips and cup-shaped surface 24 directs these strips throughopening 6 into collection chamber 12. Smaller particles, in some casesproduced during the removal of harder or calcified atheroma, can bedirected towards opening 6 by the cup-shaped surface 24 and can also bedirected tangentially to the spinning cutting element outer edge 23, insome cases past opening 6 and in this event not collected in chamber 12.

Referring now to FIG. 5, catheter 2A is shown wherein the same orsimilar reference numbers of catheter 2A refer to the same or similarstructures of catheter 2 and all discussion concerning the same orsimilar features of catheter 2 are equally applicable here unless notedotherwise. Compared to catheter 2, catheter 2A has improved materialcollection capability and is additionally comprised of lumen 4A incutting element 4, lumen 20A in connecting shaft 20, rotating fitting atcutter driver 5 (not shown), fluid source (not shown) and vent holes 31in wall of collection chamber 12. Cutting element 4 and connecting shaft20 are attached by bonding, welding, molding, pressure fit, gasketedmechanical seal, or other means so as to form a leak-tight fluidconnection between lumens 4A and 20A. Rotating fitting at cutter driver5 is attached to connecting shaft 20 and to fluid source in a similarmanner so as to form a fluid tight connection between the fluid sourceand rotating connecting shaft 20. In some embodiments lumen diametersand lengths are sized so as to permit fluid flow rates of 0.5 to 50cc/min, including 0.5, 1, 2, 5, 10, 20, or 50 cc/min, or other flowrates at a driving pressure of 50 psi (345 kilopascal). In otherembodiments these flow rates are achieved at driving pressures of 1, 5,10, 20, 100 or 150 psi (6.9, 35, 69, 140, 690, or 1000 kilopascal), orat pressures therebetween.

Vent holes 31 allow fluid to flow out of interior 68 of collectionchamber 12 without allowing significant particles of material to passtherethrough. In one embodiment, vent hole diameter is 50 microns. Inother embodiments vent hole diameter is from 25 to 200 microns,including 25, 35, 65, 80, 100, 150 or 200 microns. The number, spacingand distribution of vent holes 31 can vary. In various embodiments, 10to 200 vent holes are contemplated and the number of vent holes can befrom 10 to 200, including 10, 20, 30, 50, 75, 100, or 200. The holes canbe uniformly or non-uniformly distributed over the outer surface ofcollection chamber 12. In one embodiment more than half of the holes aredistributed over the proximal half of the outer surface of collectionchamber 12 so that flow from interior 68 of collection chamber 12 ispreserved as holes of the collection chamber become blocked by particlesand fragments. In another embodiment, to encourage fluid topreferentially flow out of vent holes 31 as opposed to out of opening 6,the aggregate hydraulic resistance of fluid passing through all ventholes is less than the hydraulic resistance of fluid passing throughopening 6.

In operation, catheter 2A is advanced through vessel V with cuttingelement 4 exposed through opening 6. Cutting element 4 separates largefragments F of atheromatous material M from luminal surface LS of vesselV and cup-shaped surface 24 of cutting element 4 directs said fragmentsthrough opening 6 into interior 68 of collection chamber 12. The fluidsource forces pressurized fluid (such as physiological saline solution)through lumens 20A, 4A before, during or after rotation of cuttingelement 4, or any combination of before, during or after rotation ofcutting element 4. Fluid exits lumen 4A of cutting element 4 indirection of arrow A and flows into interior 68 of collection chamber 12and out of vent holes 31. Small particles P, generated by cuttingelement 4 acting on material M, are carried by fluid flow into distalregion 68 d of interior 68 of collection chamber 12.

Referring to FIG. 6, another catheter 2B is shown wherein the same orsimilar reference numbers of catheter 2B refer to the same or similarstructures of catheter 2 and all discussion concerning the same orsimilar features of catheter 2 are equally applicable here unless notedotherwise. Compared to catheter 2, catheter 2B has improved materialcollection capability and is additionally comprised of tube 7, fluidsource (not shown) and vent holes 31 in wall of collection chamber 12.Tube 7 is attached to the fluid source with a leak-tight fluidconnection such as a gasketed mechanical seal in the vicinity of cutterdriver 5. The fluid source, in some embodiments, provides flow only whencutter 4 is rotating, for example by means of a valve, so as to preventinfusion of excessive fluid into a patient. The fluid source can provideflow before, during or after rotation of cutting element 4, or anycombination of before, during or after rotation of cutting element 4. Inother embodiments the fluid is comprised of radiopaque substances, suchas contrast media, to facilitate visualization of the amount of materialwithin collection chamber 12. The distal end of tube 7 can be orientedin any direction ranging from towards the side wall of collectionchamber 12 to towards the distalmost end of collection chamber 12. Inone embodiment the distal end of tube 7 is oriented towards distalregion 68 d of interior 68 of collection chamber 12. In otherembodiments tube 7 has a one way valve that allows flow distally throughthe tube but prevents flow proximally through the tube so as to preventblood or debris from entering tube 7 and potentially clogging the lumenof tube 7. In some embodiments the lumen diameter and length of tube 7are sized so as to permit fluid flow rates of 0.5 to 50 cc/min,including 0.5, 1, 2, 5, 10, 20, or 50 cc/min, or other flow rates at adriving pressure of 50 psi (345 kilopascal). In other embodiments theseflow rates are achieved at driving pressures of 1, 5, 10, 20, 100 or 150psi (6.9, 35, 69, 140, 690, or 1000 kilopascal), or at pressurestherebetween. Vent holes 31 have structure and functionalcharacteristics as described above for catheter 2A.

In another embodiment of catheter 2B, fluid is infused through lumen 21of catheter 2 instead of being infused through the lumen of tube 7. Inthis embodiment fluid passages (not shown) can be provided in ramp 16such that fluid will flow distally through ramp 16 and exit from ramp 16into interior 68 of collection chamber 12.

In operation, catheter 2B is advanced through vessel V with cuttingelement 4 exposed through opening 6. Cutting element 4 separates largefragments F of atheromatous material M from luminal surface LS of vesselV and cup-shaped surface 24 of cutting element 4 directs said fragmentsthrough opening 6 into interior 68 of collection chamber 12. The fluidsource forces pressurized fluid (such as physiological saline solution)through tube 7 before, during or after rotation of cutting element 4, orany combination of before, during or after rotation of cutting element4. In some embodiments the fluid is comprised of radiopaque dye and theamount of plaque in the tip is visualized. Fluid exits the lumen of tube7 in the direction of arrow B and flows into interior 68 of collectionchamber 12 and out of vent holes 31. Small particles P, generated bycutting element 4 acting on material M, are carried by fluid flow intodistal region 68 d of interior 68 of collection chamber 12.

Referring to FIG. 7, another catheter 2C is shown wherein the same orsimilar reference numbers of catheter 2C refer to the same or similarstructures of catheter 2 and all discussion concerning the same orsimilar features of catheter 2 are equally applicable here unless notedotherwise. Compared to catheter 2, catheter 2C has improved materialcollection capability and is additionally comprised of lumen 4C incutting element 4, lumen 20C and holes 20D in connecting shaft 20,impeller 9, inlet holes 32 in catheter 2 and vent holes 31 in the wallof collection chamber 12. Cutting element 4 and connecting shaft 20 areattached by bonding, welding, molding, pressure fit, gasketed mechanicalseal, or other means so as to form a leak-tight fluid connection betweenlumens 4C and 20C. Holes 32 allow passage of fluid from lumen L ofvessel V into lumen 21 and holes 20D allow passage of fluid from lumen21 into lumen 20C. In some embodiments lumen diameters and lengths aresized so as to permit fluid flow rates of 0.5 to 50 cc/min, including0.5, 1, 2, 5, 10, 20, or 50 cc/min, or other flow rates at a drivingpressure of 50 psi (345 kilopascal). In other embodiments these flowrates are achieved at driving pressures of 1, 5, 10, 20, 100 or 150 psi(6.9, 35, 69, 140, 690, or 1000 kilopascal), or at pressurestherebetween. Impeller 9 is fixedly attached to connecting shaft 20 byadhesive bond, welding, mechanical interlock, or other means.

Referring to FIG. 7A, impeller 9 is comprised of metal, plastic, orother materials including but not limited to stainless steel, nitinol,polyoxymethylene (commercially available under the trade designationDELRIN®), polyether block amide (commercially available under the tradedesignation PEBAX®), polyamide, nylon 12, polyester, or other materials.Impeller 9 may be a separately fabricated component that is attached toconnecting shaft 20 by welding, adhesive bond, or other means, or may beintegrally formed from the shaft. In some embodiments the impeller iscomprised of 1 to 10 or more turns, including 1, 2, 3, 4, 6, 8, or 10turns (four turns 9 e are illustrated in FIG. 7A). Pitch angles 9 a of10 to 75 degrees, including 10, 20, 30, 45, 60 or 75 degrees, arecontemplated and pitch spacing 9 b may be uniform or varied along thelength of impeller. Impeller land width 9 c may also vary along thelength of the impeller. In some embodiments clearance 9 d between theouter diameter of impeller 9 and inner diameter of catheter 2 may befrom 0.000 to 0.010 inch (0.000 to 0.025 cm), including 0.000, 0.001,0.002, 0.003, 0.004, 0.007 or 0.010 inch (0.000, 0.0025, 0.0051, 0.0076,0.010, 0.018 or 0.025 cm) or in amounts therebetween. In otherembodiments there may be an interference fit or negative clearance 9 dbetween the outer diameter of impeller 9 and inner diameter of catheter2 in the amount of from 0.0005 to 0.002 inch (0.0013 to 0.0051 cm),including 0.0005, 0.001 or 0.002 inch (0.0013, 0.0025 or 0.0051 cm) orin amounts therebetween. In further embodiments dimensions of impeller 9and diameter of lumen 21 may be varied so as to generate fluid flowrates of 0.5 to 50 cc/min, including 0.5, 1, 2, 5, 10, 20, or 50 cc/min,or other flow rates when the impeller is rotating at 1,000, 2,000,4,000, 8,000, 16,000 or 24,000 RPM or at rotational speeds therebetween.Vent holes 31 have structure and functional characteristics as describedabove for catheter 2A.

In operation, catheter 2C is advanced through vessel V with cuttingelement 4 exposed through opening 6. Cutting element separates largefragments F of atheromatous material M from luminal surface LS of vesselV and cup-shaped surface 24 of cutting element 4 directs said fragmentsthrough opening 6 into interior 68 of collection chamber 12. Impeller 9,rotating in the direction indicated by arrow D, draws fluid (such asblood) from lumen L of vessel through holes 32 and into lumen 21,pressurizes the fluid and forces the pressurized fluid through holes20D, lumen 20C and lumen 4C during rotation of cutting element 4. Fluidexits lumen 4C of cutting element 4 in the direction of arrow C andflows into interior 68 of collection chamber 12 and out of vent holes31. Small particles P, generated by cutting element 4 acting on materialM, are carried by fluid flow into distal region 68 d of interior 68 ofcollection chamber 12.

Cutting element 40 (see FIGS. 8 and 8A) can be used in place of cuttingelement 4 in any of catheters 2, 2A, 2B, 2C or 2D. Cutting element 40 issimilar to cutting element 4 wherein the same or similar referencenumbers of cutting element 40 refer to the same or similar structures ofcutting element 4 and all discussion concerning the same or similarfeatures of cutting element 4 are equally applicable here unless notedotherwise. Compared to cutting element 4, cutting element 40 isadditionally comprised of one or more channels 42 and one or more holes44. During rotation of cutting element 40 in direction E fluid (such asblood) enters channel 42 at outer edge 23 of cutting element 40 andexits distally through hole 44. Channel 42 and hole 44 can be fabricatedinto cutter 40 by drilling, electro-discharge machining (EDM), or othermeans. In one embodiment, cutting element 40 is made in 2 pieces, onewith channel 42 cut therein, the other with cutting edge 22, cup-shapedsurface 24, raised element 26 (if used) and hole 44 formed therein, thetwo pieces being subsequently joined together by welding, soldering,brazing, adhesive bonding, mechanical interlock or other means. In someembodiments holes 44 are not positioned along axis LA of cutting element40. The number of channels and holes, channel widths 42W, channellengths 42L, and hole 44 diameters may be varied so as to generate fluidflow rates of 0.5 to 50 cc/min, including 0.5, 1, 2, 5, 10, 20 or 50cc/min, or other flow rates when cutting element 40 is rotating at1,000, 2,000, 4,000, 8,000, 16,000 or 24,000 RPM or at rotational speedstherebetween.

In operation, cutting element 40 is rotated in the direction of arrow Eduring use within a vessel V as previously described for, for example,catheter 2A. Cutting element 40 separates large fragments F ofatheromatous material M from luminal surface LS of vessel V andcup-shaped surface 24 of cutting element 4 directs said fragmentsthrough opening 6 into interior 68 of collection chamber 12. Cuttingelement 40, rotating in the direction indicated by arrow E, forces fluid(such as blood) from lumen L of vessel V into channel 42 and into hole44 during rotation of the cutting element. Fluid exits hole 44 ofcutting element 40 in the general direction of longitudinal axis LA andflows into interior 68 of collection chamber 12 and out of vent holes31. Small particles P, generated by cutting element 40 acting onmaterial M, are carried by fluid flow into distal region 68 d ofinterior 68 of collection chamber 12.

Referring to FIG. 9, another catheter 2D is shown wherein the same orsimilar reference numbers of catheter 2D refer to the same or similarstructures of catheter 2 and all discussion concerning the same orsimilar features of catheter 2 are equally applicable here unless notedotherwise. Compared to catheter 2, catheter 2D has improved materialcollection capability and is additionally comprised of drive shaft 33and one or more propellers 34. In various embodiments drive shaft 33 andpropeller 34 may be comprised of metals such as stainless steel,cobalt-chromium-nickel-molybdenum-iron alloy (commercially availableunder the trade designation Elgiloy®), or other metals, or polymers suchas polyester, polyamide, nylon 12, liquid crystal polymer, or otherpolymers. Drive shaft 33 is attached to cup-shaped surface 24 of cuttingelement 4 and propeller 34 is attached to drive shaft 33, in someembodiments by welding, brazing, soldering, overmolding, mechanicalinterlock, adhesive bonding or other attachment means. In oneembodiment, drive shaft 33 is attached to cup-shaped surface 24 ofcutting element 4 along longitudinal axis LA. Drive shaft 33 is flexibleenough to bend between axis LA of cutting element and the longitudinalaxis LACC of collection chamber 12. In one embodiment (FIG. 9) driveshaft 33 is long enough to locate propeller 34 near the distal end ofcollection chamber 12. In another embodiment (FIG. 10A) drive shaft 33is only long enough to locate propeller 34 immediately distal to opening6. Drive shaft 33 may be of any length at or between these two extremes.Propeller 34 is oriented to propel fluid (for example, blood) in adistal direction. The pitch of propeller 34 may be varied so as togenerate fluid flow rates of 0.5 to 50 cc/min, including 0.5, 1, 2, 5,10, 20 or 50 cc/min, or other flow rates when propeller 34 is rotatingat 1,000, 2,000, 4,000, 8,000, 16,000 or 24,000 RPM or at rotationalspeeds therebetween. Vent holes 31 have structure and functionalcharacteristics as described above for catheter 2A.

In operation, catheter 2D is advanced through vessel V with cuttingelement 4 exposed through opening 6. Cutting element 4 separates largefragments F of atheromatous material M from luminal surface LS of vesselV and cup-shaped surface 24 of cutting element 4 directs said fragmentsthrough opening 6 into interior 68 of collection chamber 12. Propeller34 propels fluid distally in interior 68 of collection chamber 12 andout through vent holes 31, thereby causing fluid (such as blood) to bedrawn into collection chamber 12 through opening 6. Fluid flow intoopening 6 carries small particles P, generated by cutting element 4acting on material M, into distal region 68 d of interior 68 ofcollection chamber 12.

In another embodiment of catheter 2D, a paddle is attached to cup-shapedsurface 24 of cutting element 4 instead of attaching drive shaft 33 andpropeller 34 to cup-shaped surface 24. Some embodiments of a paddle areillustrated in FIGS. 9A, 9B and 9C and labeled as paddles 35A, 35B and35C, respectively. The paddles 35A, 35B, 35C are illustrated with cutter4 in a stored position. The paddles may be comprised of wire having, insome embodiments, a rectangular cross section. The wire is twisted intoa helical configuration as shown in the figures. Paddles 35A, 35B, or35C cause fluid in interior 68 of chamber 12 to move distally duringrotation of cutting element 4. In some embodiments wire width (themaximum distance between portions of the wire in the plane perpendicularto the longitudinal axis of the catheter), length and thickness as wellas the pitch of the helix may be varied so as to generate fluid flowrates of 0.5 to 50 cc/min, including 0.5, 1, 2, 5, 10, 20, or 50 cc/min,or other flow rates when the impeller is rotating at 1,000, 2,000,4,000, 8,000, 16,000 or 24,000 RPM or at rotational speeds therebetween.In some embodiments the wire may be from 0.002 to 0.020 inch (0.0051 to0.051 cm), including 0.002, 0.003, 0.004, 0.005, 0.007, 0.009, 0.011,0.015 or 0.020 inch (0.0051, 0.0076, 0.010, 0.013, 0.018, 0.023, 0.028,0.038 or 0.051 cm) thick, and the wire width may be from 0.010 to 0.075inch (0.025 to 0.19 cm), including 0.010, 0.015, 0.020, 0.025, 0.030,0.040, 0.050 or 0.075 (0.025, 0.038, 0.051, 0.064, 0.076, 0.10, 0.13 or0.19 cm), or at thicknesses, wire widths, or both therebetween.

In one exemplary embodiment, FIG. 9A illustrates paddle 35A comprised ofrectangular cross section wire that has been twisted into a helix thatis nearly as long as the length of collection chamber 12, having a wirewidth D1 that is 40% of the inside diameter of the collection chamber,and which has a uniform pitch length P1 over the length of the paddle.In another exemplary embodiment, FIG. 9B illustrates paddle 35Bcomprised of rectangular cross section wire that has been twisted into ahelix that is 60% as long as the length of collection chamber 12, havinga wire width D2 over the proximal portion of the paddle that is 40% ofthe inside diameter of the collection chamber and a wire width D3 overthe distal portion of the paddle that is 80% of the inside diameter ofthe collection chamber, and which has a uniform pitch length P2 over thelength of the paddle. It is contemplated that other embodiments can have3 or more different wire widths, or that the wire width may continuouslyvary over at least portions of paddle 35B. Further, wire widths of from20% of the inside diameter of the collection chamber to 95% of theinside diameter of the collection chamber are contemplated. FIG. 9Cillustrates paddle 35C comprised of rectangular cross section wire thathas been twisted into a helix that is 70% as long as the length ofcollection chamber 12, having a wire width D4 over the length of thepaddle that is 30% of the inside diameter of the collection chamber, anda pitch length P3 over a proximal portion of paddle and a pitch lengthP4 over a distal portion of the paddle. It is contemplated that otherembodiments can have 3 or more pitch lengths, or that the pitch lengthmay continuously vary over at least portions of paddle 35C. In yet otherembodiments, wire width and pitch length can both vary continuously ordiscretely over the length of a paddle.

Optionally, in some embodiments catheters 2, 2A, 2B or 2C mayadditionally be comprised of drive shaft 33 and propeller 34. In otherembodiments catheters 2, 2A, 2B or 2C may additionally be comprised ofpaddles 35A, 35B, or 35C.

In operation, catheter 2D equipped with paddle 35A, 35B, or 35C, insteadof shaft 33 and propeller 34, is advanced through vessel V with cuttingelement 4 exposed through opening 6. Cutting element 4 separates largefragments F of atheromatous material M from luminal surface LS of vesselV and cup-shaped surface 24 of cutting element 4 directs said fragmentsthrough opening 6 into interior 68 of collection chamber 12. Paddle 35A,35B, or 35C propels fluid distally in interior 68 of collection chamber12 and out through vent holes 31, thereby causing fluid (such as blood)to be drawn into collection chamber 12 through opening 6. Fluid flowinto opening 6 carries small particles P, generated by cutting element 4acting on material M, into distal region 68 d of interior 68 ofcollection chamber 12. Paddle 35 also transports fragments F into distalregion 68 d of interior 68 of collection chamber 12.

In another embodiment, fragments F and particles P are removed frominterior 68 of collection chamber 12 of catheter 2D by providing anopening at the distal end of collection chamber 12 and then rotatingpropeller 34 or paddle 35 to thereby expel debris. Further descriptionof catheters provided with an opening at the distal end of collectionchamber 12 is found in U.S. Patent Application Publication No. US2005/0222663 A1 to Simpson et. al., entitled “Debulking Catheters andMethods”, the contents of which are hereby incorporated by referenceherein. See paragraphs [0117] to [0146]. In other embodiments catheters2, 2A, 2B or 2C may additionally be comprised of shaft 33 and propeller34 or paddles 35A, 35B, or 35C and the interior of collection chamber 12may be cleaned of debris as described above for catheter 2D.

In some embodiments of catheters 2A, 2B, 2C or 2D a fluid recirculationcircuit may be established. This is especially desirable in the case oftotal or near total obstruction of distal runoff in the vessel (see FIG.10A) where, for example, material M completely occludes the vesseldistal to the material removal catheter. To establish a fluidrecirculation circuit the flow rate of fluid out of vent holes 31 mustexceed the volume of fluid entering into interior 68 of collectionchamber 12 through lumen 4A (catheter 2A), through tube 7 (catheter 2B),through lumen 4C (catheter 2C), through hole 44 of cutting element 40,or through combinations of these structures (where used). When this flowcondition occurs a negative pressure will be established in the interior68 of collection chamber 12 and fluid will flow into collection chamber12 through opening 6, thereby drawing particles P generated by thecutting element into the interior 68 of collection chamber 12 (FIGS. 10Aand 10B).

In addition to use in blood vessels the invention is envisioned to beuseful for removal of blockages in other blood flow lumens such asnatural or artificial grafts, stent-grafts, anastomotic sites, fistulae,or other blood flow lumens.

The above description and the drawings are provided for the purpose ofdescribing embodiments of the invention and are not intended to limitthe scope of the invention in any way. It will be apparent to thoseskilled in the art that various modifications and variations can be madewithout departing from the spirit or scope of the invention. Thus, it isintended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents. Further, while choices formaterials and configurations may have been described above with respectto certain embodiments, one of ordinary skill in the art will understandthat the materials and configurations described are applicable acrossthe embodiments.

1. An atherectomy catheter, comprising: a body having an opening; arotatable shaft coupled to the body; a tissue collection chamber coupledto the body and positioned distal to the cutting element; a cuttingelement coupled to the rotatable shaft, the cutting element having acutting edge; and a part for propelling fluid distally in the tissuecollection chamber, the part being selected from the group consistingof: (i) a drive shaft having a proximal end and a distal portion, theproximal end being attached to the cutting element and a propeller beingattached to the distal portion; and (ii) a paddle attached to thecutting element.
 2. The catheter of claim 1, wherein the cutting elementhas a cup-shaped surface, the cup-shaped surface being configured tore-direct tissue cut by the cutting edge in a distal direction when thecup-shaped surface moves in the distal direction.
 3. The catheter ofclaim 2, wherein the part for propelling fluid distally in the tissuecollection chamber is selected from the group consisting of: (i) a driveshaft having a proximal end and a distal portion, the proximal end beingattached to the cup-shaped surface of the cutting element and apropeller being attached to the distal portion; and (ii) a paddleattached to the cup-shaped surface of the cutting element.
 4. Thecatheter of claim 1, wherein the part for propelling fluid distally inthe tissue collection chamber is a drive shaft having a proximal end anda distal portion, the proximal end being attached to the cutting elementand a propeller being attached to the distal portion.
 5. The catheter ofclaim 4, wherein the propeller is located distally of the opening andproximally of the distal end of the collection chamber.
 6. The catheterof claim 5, wherein the propeller is located immediately distally of theopening.
 7. The catheter of claim 5, wherein the propeller is located inthe distal half of the collection chamber.
 8. The catheter of claim 4,wherein the proximal end of the drive shaft is attached to a cup-shapedsurface of the cutting element, the cup-shaped surface being configuredto re-direct tissue cut by the cutting edge in a distal direction whenthe cup-shaped surface moves in the distal direction.
 9. The catheter ofclaim 1, wherein the part for propelling fluid distally in the tissuecollection chamber is a paddle attached to the cutting element.
 10. Thecatheter of claim 9, wherein the paddle is a wire that is twisted in ahelical configuration.
 11. The catheter of claim 10, wherein the wirehas a rectangular cross section.
 12. The catheter of claim 10, whereinthe wire has a thickness from 0.002 to 0.020 inch (0.0051 to 0.051 cm).13. The catheter of claim 10, wherein the wire width is from 0.010 to0.075 inch (0.025 to 0.19 cm).
 14. The catheter of claim 10, wherein thepaddle has a wire width that is from 20 to 95 percent of an insidediameter of the collection chamber.
 15. The catheter of claim 9, whereinthe paddle has a longitudinal length that is at least 50 percent of thelongitudinal length of the collection chamber.
 16. The catheter of claim9, wherein the paddle has a longitudinal length that is at least 70percent of the longitudinal length of the collection chamber.
 17. Thecatheter of claim 17, wherein the tissue collection chamber comprisesvent holes.
 18. The catheter of claim 17, wherein the tissue collectionchamber comprises 10 to 200 vent holes.
 19. The catheter of claim 17,wherein the vent holes have a diameter of from 25 to 200 microns. 20.The catheter of claim 9, wherein the paddle is attached to a cup-shapedsurface of the cutting element, the cup-shaped surface being configuredto re-direct tissue cut by the cutting edge in a distal direction whenthe cup-shaped surface moves in the distal direction.
 21. The catheterof claim 1, wherein the collection chamber comprises a portion at adistal end that can be opened to remove cut material and particles. 22.The catheter of claim 1, wherein the cutting element is movable betweena stored position and a cutting position relative to the opening.
 23. Amethod of removing material from a body lumen, the method comprising:providing an atherectomy catheter, the atherectomy catheter comprising:a body having an opening; a rotatable shaft coupled to the body; atissue collection chamber coupled to the body and positioned distal tothe cutting element; a cutting element coupled to the rotatable shaft,the cutting element having a cutting edge; and a part for propellingfluid distally in the tissue collection chamber, the part being selectedfrom the group consisting of: (i) a drive shaft having a proximal endand a distal portion, the proximal end being attached to the cuttingelement and a propeller being attached to the distal portion; and (ii) apaddle attached to the cutting element; placing the catheter in the bodylumen; and moving the catheter in the body lumen to contact the cuttingelement with the material in the body lumen.
 24. The method of claim 23,wherein the catheter is moved in a distal direction to contact thecutting edge with the material in the body lumen.
 25. The method ofclaim 23, wherein the catheter is placed in the body lumen with thecutting element in the stored position and the catheter is moved tocontact the material with the cutting element in a cutting position. 26.The method of claim 23, wherein the body lumen is a blood vessel.